1. Field of the Invention
The invention is related to the field of communications and, in particular, to providing per-session dynamic charging caps for sessions in a communication network. More particularly, a dynamic charging cap is determined for a session (prepaid or postpaid) based on charging criteria that is defined for a party to the session.
2. Statement of the Problem
Communication networks include charging mechanisms in order to bill for calls or sessions placed over the network. The charging mechanisms may be prepaid or postpaid. For a typical postpaid session over a communication network, the switch that is serving the session transmits one or more charging request messages for the session to a postpaid server. The postpaid server processes the charging request messages to generate a Charging Data Record (CDR) for the session. The postpaid server inserts a total duration for the session in the CDR along with other session information. The postpaid server then transmits the CDR to a billing system. The billing system for postpaid sessions typically includes a rating engine that is used to rate the session. The rating may be a flat rating, such as $0.05 per minute. The rating may alternatively be a stepped rating, such as $0.05 per minute for the first five minutes, $0.08 per minute for the next five minutes, and then $0.12 per minute for the remainder of the session. The billing system then calculates a charge (i.e., cost or fee) for the session based on the total duration and the rating.
For a typical prepaid session over a communication network, the switch that is serving the session transmits a charging request message for the session to a prepaid server. The prepaid server identifies a prepaid account balance for the party to the session, and determines a rating for the session (either flat rating or stepped rating). The prepaid server then grants a credit quota based on the prepaid account balance and the rating, and transmits the credit quota to the switch. The switch then performs budget control by decrementing the credit quota as the session progresses. When the credit quota is empty, the switch again transmits a charging request message for the session to the prepaid server requesting a new credit quota. If there is a sufficient balance in the prepaid account of the party, then the prepaid server grants another credit quota and transmits the credit quota to the switch. The switch then performs budget control by decrementing the credit quota as the session progresses. This process continues until either the session ends or the prepaid account for the party becomes empty. The party is thus charged for the prepaid session based on the duration of the session.
One problem with present charging systems is that charging is based on the total duration of a session. Service providers may want more flexibility in how charging is performed for sessions. For instance, a service provider may want to offer a promotion where the first five minutes of a session is charged, while the remainder of the session is free. Unfortunately, present charging systems are not flexible to charge for sessions in this manner.